This invention relates to a one-way clutch and more particularly to an improved, low cost, light weight one-way clutch.
One-way clutches are employed for a wide variety of uses. A one-way clutch functions, as is well known in this art, to rotatably couple a driving element to a driven element under certain conditions but also so as to permit overrunning of the driven element relative to the driving element. For example, a one-way clutch may be employed in the connection between a starter motor driven gear and an engine shaft for rotating the engine shaft when the starter motor is energized and the engine is not running. However, once the engine begins to run, the one-way clutch permits overunning of the engine shaft relative to the starter driven gear so that the starter motor can be stopped.
One-way clutches normally use an outer member, an inner member, and wedging members that are operatively interposed between the outer and inner members for establishing a driving relationship with them under certain conditions. The wedging members are normally urged into engagement with a wedging surface of the outer member and the inner member by means of a spring arrangement. The type of spring arrangements normally used for this purpose have comprised coil compression springs which must be supported in bores formed in the outer member and which engage plungers which, in turn, act against the wedging member so as to hold it in engagement with the inner and outer member surfaces. Hence, a substantial number of parts are required by the prior art type of devices. Furthermore, due to the relatively small size, in many applications, it is very difficult to insert and install these minute components upon assembly.
It is, therefore, a principal object of this invention to provide an improved one-way clutch.
It is a further object of this invention to provide an improved and simplified biasing spring arrangement for the wedging members of a one-way clutch.
It is a yet further object of this invention to provide a one piece biasing and actuating member for exerting a biasing force on the wedging members of a one-way clutch.
In conjunction with the construction of one-way clutches as aforedescribed, the outer member is provided with recesses in which the wedging members are received. The coil springs are received in bores which intersect these recesses and thus the outer member must be assembled to include the spring and wedging members before the inner members are put in place. Obviously, this is a very complicated arrangement and requires some device for holding the wedging members against the springs while the inner member is assembled into the outer member containing the wedging members and the springs. Obviously, this is a high labor intensive work and adds considerably to the cost of these components.
It is, therefore, a further object of this invention to provide an improved and simplified arrangement which facilitates the manufacture and assembly of one-way clutches.
It is a further object of this invention to provide an improved and simplified one-way clutch construction in which the amount of labor necessary to assemble the clutch is reduced.
From the foregoing description, it should be readily apparent to those skilled in the art that the wedging of the wedging members between the inner and outer members of the one-way clutch creates significant forces on the outer member which must resist these wedging forces to avoid failure. As a result, it has been the practice to employ as the outer member a large and heavy piece formed from a very high strength material so as to absorb the forces encountered. As a result, the one-way clutches of the prior art type have been quite heavy.
Recently, it has been proposed to employ two separate pieces as the outer member of the one-way clutch. One of these pieces forms only a caging function for the wedging members and hence may be relatively light weight and may be formed from relatively low tensile strength material such as plastics and/or sintered metals. The other member actually provides the wedging surface against which the wedging member reacts and thus is formed from a higher strength material. However, the overall weight of the assembly can be reduced by this type of construction. It is, however, necessary to attach together the two members which form the wedging and caging functions and this has been done, in the previously proposed constructions, by means of separate fastening means.
It is, therefore, a still further object of this invention to provide an improved and simplified outer member for a one-way clutch which may be made up of two pieces and which does not require a separate fastening means for attaching these two pieces to each other.